When you're hunting down your next vacation spot it's easy to get caught up finding the cheapest hotels and flights. If you're really looking to keep the vacation cheap, The New York Times also points out that it's a good idea to check the cost of busses or trains as well.

Speaking with student travel guide writer Mark Warren, he points out that ground cost can add up quickly:

I'd recommend a place that has cheap ground transportation. That's a tough matrix to pin down: how much it costs to get there versus the costs once on the ground. It's much cheaper to fly to Europe than, say, Vietnam, but if train tickets cost $200 each, those add up. So look up regional train lines and bus companies to get a sense of their prices before deciding where to go.

Warren notes that this especially the case if you're planning a regional trip and hitting up several countries. Instead of picking a flight based on where you want to go, pick the cheapest flight in the area, and then use regional carriers or ground transportation to get around. After all, if you're spending a lot of time finding the best deals on flights, the last thing you want is a bunch of surprise costs just to get around the area.